Web transport apparatus

ABSTRACT

Web transport apparatus utilizing web transport rollers having a longitudinal rib on the web-contacting surface. The rib is formed of a spongy material whereby a plurality of webs having slippery surfaces may be transported simultaneously in parallel paths with good tracking characteristics.

United States Patent Inventor Thomas A. Chuhta [56] References Cited Rochester. N.Y. UNITED STATES PATENTS $53 1969 3,042,281 7/1962 Balvin et al. 226/191(X) Patented y 197] 3,110,432 11/1963 Smith 226/189(X) Assignee Eastman Kodak Com any Primary ExaminerAllen N. Knowles Rochester, N.Y Assistant ExaminerGene A. Church Att0rneysWalter O. Hodsdon and Robert L. Randall WEB TRANSPORT APPARATUS 10 Claims 5 Drawmg ABSTRACT: Web transport apparatus utilizing web transport US. Cl 226/191 rollers having a longitudinal rib on the web-contacting sur- Int. Cl B65h 17/20 face. The rib is formed of a spongy material whereby a plurali- Field of Search 226/ 190- ty of webs having slippery surfaces may be transported simul- -193, 189, 171; 29/121, 132 taneously in parallel paths with good tracking characteristics.

x F 24 l PATENTED mwzslsn 3.580.452

THOMAS A. CHUHTA INVEVTO WQN wa M A TTOHNEYS BACKGROUND OF THE'INVENTION ln high-volume commercial photographic processing operations, photographic prints are exposed on continuous webs of sensitized paper which are then passed through the various processing solutions. Normally, the paper is fed in serpentine fashion through a plurality of tanks containing the necessary chemicals to effect the development, f xing, and washing of the photographic print. A common type of photographic print processor utilizes a plurality of vertically spaced pairs of rollers over which the photographic paper is threaded. The lower roller of the pair is generally immersed in the processing solution. Processing apparatus capable of processing photographic prints at high rates of production commonly utilize tanks and transport rollers which are substantially wider than the width of the web of photographic paper being passed therethrough so that two or more webs or lines may be transported through the processor simultaneously in parallel paths.

Various drive methods are employed to pull the web of photographic paper through the processing apparatus. One such drive method incorporates a pacer roller at the outlet end of the processor which grips the web of photographic paper and pulls it through the preceding processing stations. However, this method generates high tensions in the web clue to the friction in the guidah'ce rollers and the viscous drag of the processing solutions on the photographic paper. Another type of web drive system utilizes several of these pacer rollers spaced along the length of the processor. While this reduces somewhat the amount of tension generated in the web, it still does not provide the optimum drive characteristics. As a result, tendency drive systems have been adopted whereby each of the top rollers of the vertically spaced roller pairs are driven through a clutch arrangement from a power source. The clutch arrangement permits the adjustment of the drive so that the paper is satisfactorily driven and yet the roller is not driven with sufficient force to generate an undesirably high tension in the photographic paper. Thus, a driving force is transmitted through the roller to the photographic paper until the tension in the paper reaches a predetermined amount as sensed by the drive clutch and the clutch slips. Generally. such drive rollers utilize a hard, cylindrical rubber or plastic surface over which the web is threaded. Heretofore, tendency web drive systemshave been satisfactory, even in systems wherein two or three lines of photographic paper are threaded in parallel over the drive rollers. Any variation in the tensions encountered in the various webs traveling in parallel through such a process have been accommodated by stretching of the paper passing over the rollers.

However, with the introduction of photographic papers having resin-coated or plastic-coated surfaces, which tend to be quite slippery, the tracking characteristics of the paper through processors utilizing such tendency drive transport systems have deteriorated. The use of photographic paper utilizing plastic-coated or resin-coated surfaces derive many advantages 'and benefits through the processor as noted in US. Pat. No. 2,773,769. However, it has been found that with such photographic paper, the surface smoothness is so great, ie it is very slippery, especially when wet by processing solutions, that unless the tension in each web is maintained within close limits in the transport system, the web having a tension below the tension of the parallel webs tends to wander as it passes over the drive rollers, and may even overlap the adjacent web. This can result in one web sticking to another, in preventing the processing solution from reaching a portion of one of the webs, or other undesirable effects.

Various attempts have been made to correct the inability of web transport arrangements to properly track such webs having slippery surfacesplt has been found that precision fabrication of the transport rollers and the bearings and frames, along with precise alignment of the elements in the apparatus, provides improved tracking characteristics. However, use of such precision apparatus has shown that as the various components wear, permitting such deviation in the fit that tracking problems reoccur. Moreover, this answer to the tracking problem is not applicable to existing machines so that they cannot be thus adapted to handle such slippery webs.

Another solution that has been attempted is to provide the drive rollers with individual sections for each web of photographic paper passing therethrough. While this does solve the tracking problem, such an arrangement has disadvantages which override the potential advantages. Utilizing such a divided roller, it is not possible to simply adapt the processing apparatus for handling webs of other than a single size. With a web transport system utilizing a solid roller, it is possible to process for example, three 35-inch webs of photographic paper simultaneously or, by merely threading a different size paper through the processor, two 5-inch webs of paper, or a single 8-inch wide web of paper. Utilizing divided rollers necessitates the replacement of all the rollers in the processor when the width of paper is changed.

Attempts have also been made at using O-rings around the rollers to maintain the webs in proper alignment. However, it has been found that such slippery webs are not restrained by the O-rings and the webs merely climb over the O-rings. If sufficiently large O-rings are utilized to restrain the webs, it has been found that sufficiently high forces are developed that the edges of the web are torn and damaged. I

It has thus been .found necessary to limit the number of webs which are threaded through a processor when utilizing such plastic-coated or resin-coated photographic paper in order to provide sufficient spacing between adjacent webs to prevent overlapping when one of the web wanders from its prescribed path. Thus, under these circumstances less than the full design capacity of the processor is available to the film processor substantially reducing his throughput per machine and increasing the operating cost and the capital investment necessary.

It can thus be seen that a web transport apparatus which can handle slippery webs of plastic-coated or resin-coated photographic paper without the web deviating from the predetermined path would be extremely advantageous. Moreover, inasmuch as photographic processors utilize a large number of drive rollers, if a relatively simple conversion were possible to permit handling such slippery webs, it would be very economically advantageous. Such a conversion requiring little downtime of the apparatus and little modification of the existing apparatus would be even more advantageous.

SUMMARY OF THE INVENTION Accordingly, the present invention provides a web transport roller member having an-axis and a peripheral outer web contacting surface arranged to rotate about the axis. The major portion of the web-contacting surface is cylindrical and is disposed substantially coaxially about the axis. A rib portion of the web-contacting surface is spaced from the axis at a distance greater than the major portion of the web-contacting surface. The rib portion of the web-contacting surface extends along a substantial portion of the length of the roller and is formed of a substantially resilient material whereby a plurality of webs having a slippery surface may be transported simultaneously without deviating from the predetermined path.

More particularly, the ribbed portion has a substantially rectangular cross section and extends above the major portion of the web-contacting surface. The ribbed portion is preferably formed of foam rubber.

Furthermore, the present invention provides the web transport apparatus arranged to simultaneously transport a plurality of webs having a slippery surface. The transport apparatus comprises a plurality of roller members each having an axis and a peripheral outer web-contacting surface arranged to rotate about the axis. A major portion of the web-contacting surface is cylindrical and is disposed substantially coaxially about the axis. Each roller member has a rib portion extending outwardly from the web-contacting surface. The rib portion extends longitudinally along a substantial length of the roller and is formed of a substantially resilient material. A drive means is arranged to rotate the roller members to drive the webs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a schematic illustration of a web transport apparatus embodying a preferred embodiment of the present invention;

FIG. 2 is an enlarged perspective view of one web transport roller showing the rib configuration; and

FIGS. 3-5 illustrate cross-sectional views of alternate embodiments of the present invention.

DESCRIPTION OF A PREFERRED EMBODIMENT A web transport apparatus utilizing the present invention is illustrated in FIG. 1 and comprises a plurality of rollers, three of which are shown here. The upper rollers and the bottom rollers 12 cooperate as pairs and are arranged to rotate on shafts l4 and 16. A plurality of webs of photographic paper 18 are threaded over rollers 10 and 12 in a serpentine path. A drive means, such as motor 20 is connected to the top rollers through a clutch means, not shown. Thus, the top rollers 12 are driven by the motor 20 and transmit the driving force to the webs 18 transporting them through the processor. In the preferred embodiment illustrated, the top rollers 12 have a generally cylindrical configuration, with a major portion of the web-contacting surface 22 being disposed coaxially about the axis upon which the roller member rotates. As may clearly be seen in FIG. 2, the roller member is provided with at least one rib portion 24 which has an outer web-contacting surface 26 spaced from the roller axis at a distance greater than the major portion of the web-contacting surface 22. The major portion of the web-contacting surface, or the cylindrical portion of the roller, is formed of a substantially hard nonresilient material such as hard rubber or plastic and presents a smooth surface contacting the web passing thereover. The rib.portion 24 is preferably formed of a resilient material which also has high surface friction characteristics, such as foam rubber.

It has been found that the utilization of a web transport roller member having a longitudinally extending rib portion 24 provides a web transport apparatus which can transport a plu rality of parallel webs of photographic paper even when the surfaces of the web are extremely slippery, such as plasticcoated or resin-coated paper which has been wet by processing solutions. Moreover, it has been found that the tracking characteristics of ordinary photographic paper'are improved with the utilization of the arrangement of the present invention.

While not intending to limit the scope of the present invention, it is believed that the resilient rib functions as follows to minimize the tendency of slippery webs to wander over the surface of the roller as it is transported through the processor. Primarily, the flexible rib accommodates slight deviations in the tension existing in adjacent webs as they pass over a roller. Thus, if one web is tighter than another, the rib 24 is deflected under the tighter web while the rib still contacts and transports the adjacent webhaving a lower tension. It is believed that without the rib, when parallel webs are transported over a roller, the surface of the roller is in good contact only with the web having the higher tension. Thus, the adjacent webs, which are under somewhat lower tension, are free from the restraining forces of the web-contacting surface of the roller and, in prior art arrangements, tend to wander and eventually overlap the adjacent web with the above-noted consequences. Additionally, it is believed that the flexible major of the rib permits the web to be slightly imbedded therein which tends to minimize or eliminate the tendency of the web to move laterally across the surface of the web transport roller. Finally, it is believed that the rib portion provides a camming action, picking -up the web as it approaches the transport roller and lifting it up and over the top of the roller, drawing along any slack which may have been generated in the web approaching the roller. Thus, any slack which occurs in the web is progressively moved to the outlet end of the processor and thus does not accumulate at any one point providing the possibility of the web deviating from its predetermined path.

Alternative embodiments of the rib portion of the drive roller of the present invention are illustrated in FIGS. 3-5. The arrangement illustrated in FIG. 3 utilizes a resilient rib portion 28 having a smooth outer surface 30 which forms a smooth transition with the cylindrical portion 32 of the roller 10. It has been found that this arrangement, so long as the rib is formed of a resilient material such as foam rubber, provides substantially the same operation and advantages of the rib arrangement illustrated in FIG. 2. The arrangement illustrated in FIG. 4 shows a rib construction formed of a flattened tubular member 34, which is attached to the outer surface 36 of the roller 10. The arrangement illustrated in FIG. 5 provides a double resiliency whereby the rib portion 38, which is formed of a resilient material such as foam rubber, is resiliently mounted in a slot 40 formed in the outer surface 42 of the roller 10 which slot is provided with a plurality of spring members 44 which permit the rib portion to deflect even more than the natural resiliency of the rib itself.

While in the preferred embodiment the rib portion is described as being on the drive roller, it will be appreciated that similar advantages may also be obtained by providing both driven and nondriven rollers in the transport apparatus with such raised rib portions to eliminate the deviation of the web from the predetermined path. Moreover, while foam rubber has been recited as the material from which the rib portion is formed, it will be appreciated that other materials having similar resilient characteristics may likewise be used. Furthermore, while the rib portion has been illustrated as extending substantially continuously along the length of the roller, a plurality of closely spaced small segments of resilient material may be utilized for the rib portion and still achieve the desired web-tracking characteristics.

Accordingly, it will be seen that the present invention provides a web transport apparatus utilizing a substantially cylindrical roller having a resilient rib portion extending outwardly therefrom which provides the necessary tracking force to permit the transport of several parallel webs having extremely slippery surfaces. Moreover, with the present invention, it is possible to simply and economically convert preexisting web transport apparatus in order to permit the transportation of such slippery webs by merely attaching a resilient rib portion to the outer periphery of the web transport rollers, such as by adhesive or by heat sealing. This may even be accomplished in some processors without necessitating the removal of the transport rollers from the processing apparatus. Thus the downtime necessary to permit conversion is minimized.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

lclaim:

l. A web transport roller member having an axis and a peripheral outer web contacting surface arranged to rotate about said axis, a major portion of said web-contacting surface being cylindrical and disposed substantially coaxially about said axis, a rib portion of said web-contacting surface having an axis spaced from said roller axis at a distance greater than said major portion of said web-contacting surface, said rib portion of said web-contacting surface extending along a substantial portion of the length of said roller and formed of a substantially resilient material.

2. The invention according to claim 1 wherein said rib portion has a substantially rectangular cross section which extends above the majorportion of said web-contacting surface.

3. The invention according to claim 1 wherein said resilient rib material is resiliently connected to said roller member.

4. The invention according to claim 1 wherein said rib portion extends axially along the length of said roller.

5. The invention according to claim 1 wherein said rib portion is formed of foam rubber.

6. A web transport roller member arranged to simultaneously transport a plurality of slippery webs, said roller member having an axis and a peripheral outer web contacting surface arranged to rotate about said axis, a major portion of said webcontacting surface being cylindrical and disposed substantially coaxially about said axis, and at least one rib portion of said web-contacting surface having an axis spaced from said roller axis at a distance greater than said major portion of said webcontacting surface, said rib portion of said web-contacting surface extending longitudinally along substantially the length of said roller, said major portion of said web-contacting surface formed of a substantially rigid smooth material, said rib portion of said web-contacting surface formed of a resilient friction material.

7. The invention according to claim 6 wherein said rib portion is formed of foam rubber.

8. The invention according to claim 6 wherein said rib portion is formed of a deformable tubular member.

9. Web transport apparatus arranged to simultaneously transport a plurality of webs having a slippery surface, said transport apparatus-comprising a plurality of roller members each having an axis and a peripheral outer web contact surface arranged to rotate about said axis, a major portion of said web-contacting surface being cylindrical and disposed substantially coaxially about said axis, each roller member having a rib portion with an axis spaced from said roller axis, said rib portion extending outwardly from said web-contacting surface, said rib portion extending along substantially the length of said roller and formed of a substantially resilient material, and drive means arranged to rotate said roller members.

10. The invention according to claim 9 wherein said resilient material is foam rubber. 

1. A web transport roller member having an axis and a peripheral outer web contacting surface arranged to rotate about said axis, a major portion of said web-contacting surface being cylindrical and disposed substantially coaxially about said axis, a rib portion of said web-contacting surface having an axis spaced from said roller axis at a distance greater than said major portion of said web-contacting surface, said rib portion of said webcontacting surface extending along a substantial portion of the length of said roller and formed of a substantially resilient material.
 2. The invention according to claim 1 wherein said rib portion has a substantially rectangular cross section which extends above the major portion of said web-contacting surface.
 3. The invention according to claim 1 wherein said resilient rib material is resiliently connected to said roller member.
 4. The invention according to claim 1 wherein said rib portion extends axially along the length of said roller.
 5. The invention according to claim 1 wherein said rib portion is formed of foam rubber.
 6. A web transport roller member arranged to simultaneously transport a plurality of slippery webs, said roller member having an axis and a peripheral outer web contacting surface arranged to rotate about said axis, a major portion of said web-contacting surface being cylindrical and disposed substantially coaxially about said axis, and at least one rib portion of said web-contacting surface having an axis spaced from said roller axis at a distance greater than said major portion of said web-contacting surface, said rib portion of said web-contacting surface extending longitudinally along substantially the length of said roller, said major portion of said web-contacting surface formed of a substantially rigid smooth material, said rib portion of said web-contacting surface formed of a resilient friction material.
 7. The invention according to claim 6 wherein said rib portion is formed of foam rubber.
 8. The invention according to claim 6 wherein said rib portion is formed of a deformable tubular member.
 9. Web transport apparatus arranged to simultaneously transport a plurality of webs having a slippery surface, said transport apparatus comprising a plurality of roller members each having an axis and a peripheral outer web contact surface arranged to rotate about said axis, a major portion of said web-contacting surface being cylindrical and disposed substantially coaxially about said axis, each roller member having a rib portion with an axis spaced from said roller axis, said rib portion extending outwardly from said web-contacting surface, said rib portion extending along substantially the length of said roller and formed of a substantially resilient material, and drive means arranged to rotate said roller members.
 10. The invention according to claim 9 wherein said resilient material is foam rubber. 